Archive for September, 2015

Bearings in Agricultural Applications

Friday, September 25th, 2015

Agriculture has been at the heart of civilization since it dawned on our ancestors that food security is critical to our livelihood.

Once it was determined that a place had good food security, we began settling and growing villages. And with the growing responsibility to feed a larger community, agricultural technology began to advance as well.

Fast forward to today. There is still food scarcity present in countries all over the world. The machinery used in agricultural endeavors plays a vital role in producing efficient and stable yields so that we can continue to feed our growing communities.

Tractors

Tractors have become a primary asset in crop production and handling. And, depending on the size of the operation, they can be quite large beasts of burden.

A tractor needs to be able to operate efficiently in all types of weather and ground conditions. This can mean ensuring resistance against seal contamination from foreign debris, operating in excess mud and water, and a high potential for misalignment.

To continue to be economical, it’s also important that the tractor and its parts endure a long life, even through such harsh operating conditions.

Bearings are used in many components, including the engine, transmission, and wheel hubs of a tractor. Operating successfully, these bearings help pull and power the tractor by getting more horsepower to the ground.

Balers

Idle for most of their life, balers can be subjected to other harsh conditions during downtime, such as humidity.  This is problematic for its inner workings, especially since farmers rely on their machines to be top-notch when called on for their part.

At work, balers must operate constantly through a storm of dust. Its bearings are supporting pulleys and must continue to be reliable. Effective sealing is critical to bearing life when it comes to this machine. With proper sealing, contamination is less likely and will be less harmful.

Combines

The combine operates in the greatest extremes of all farm equipment. It lays idle for most of the year and then is called upon to be heavily operated for only a short amount of time. The wear and tear endured during operation, coupled with the amount of downtime this machine experiences puts unique strain on the bearings and other inner workings.

Like all other agricultural equipment, combines need to be utterly dependable. Unexpected maintenance and downtime can be costly not only to the farmer’s pocket, but also to the community they feed.

Combines also operate in dusty, muddy, and harsh weather and grounds conditions. Bearing designs must keep up, and seals must be ultra-reliable for these machines to do their part in the harvest.

Products and Solutions

Everything you need in agricultural applications can likely be found through NSK, Timken, and NTN. These powerhouse companies have the capability of specializing in multiple industries, and agriculture certainly is one of the largest.

There are new and innovative specialized bearings, lubricants, seals, and sensors being introduced to the market with each passing year.

Fluid Bearings and Types

Friday, September 18th, 2015

Friction is a major cause of stress, dysfunction, and failure in machines. But, it doesn’t have to rule us, if we take some simple precautionary measures.

Fluid bearings generally have very low friction (better even than mechanical bearings), are quieter and run smoother than rolling-element bearings.

They are frequently used in high load, high speed, or high precision applications where traditional ball bearings would experience a short life or potentially cause too much noise or vibration.

Fluid bearings can support their loads solely on a thin layer of liquid or gas between the bearing faces, which are typically sealed around or under the rotating shaft.

And, most fluid bearings require little or no maintenance, and have almost unlimited life. There are two basic types of fluid bearings: fluid-dynamic, and hydrostatic.

Hydrostatic Bearings

Hydrostatic bearings are externally pressurized fluid bearings that use oil, water or air, and are pressurized by a pump.

This type of fluid bearing is made up of two surfaces, and fluid that is forced by the pressurization pump in between the surfaces to keep them apart.

If the surfaces come too close together, then the pressure goes up and forces the surfaces apart again. This is effective for controlling the gap and providing low friction.

Because hydrostatic lubrication does not depend on relative motion to maintain the lubrication film, it can accommodate heavy loads at low speeds.

A downside to this type of fluid bearing is the power required by the pump, which contributes to system energy loss.

An upside, though, is long life (infinite in theory) without wear on surfaces. Additionally, hydrostatic gas bearings are among the lowest friction bearings.

Hydrodynamic Bearings

In order to pressurize the fluid between its surfaces, hydrodynamic bearings rely on the high speed of the journal (this is the part of the shaft resting on the fluid).

This high speed bearing rotation essentially pulls the fluid onto the inner surface of the bearing, forming a lubricating wedge under or around the shaft.

Once running, hydrodynamic bearings float the load on this self-renewing film of lubricant. Various load types are possible with these bearings. Thrust bearings support axial loads, and radial loads can be supported by journal bearings. Journal bearings are the simplest form of hydrodynamic bearings.

Hydrodynamic bearings are used in rotary applications, and may require external pressure on one of the bearing pads or a secondary bearing to avoid excess friction when starting rotation.

You’ll find these bearings typically in industrial applications such as in steam and gas turbines, hydroelectric generators, electric motors, cooling pumps, and rock crushers. They are also commonly found on ships in their blowers, clutch, auxiliary machinery, and pumps.

3 Main Reasons for Lubrication Failure

Friday, September 11th, 2015

It’s been around for thousands of years. We’ve used it since the dawn of the wheel. So, why does lubrication still seem to be a major issue in industries today?

Well, there’s not exactly a simple answer to that question. The short answer is – it’s complicated.

Really! Technologies have improved and expanded to major levels we never even thought possible 100 years ago.

Nowadays, there are so many different moving parts, new materials we aren’t familiar working with, and so much more to keep track of, including proper lubrication for all those parts.

Today, we’ll go through 3 main areas where lubricant failures occur.

Moisture

This is another common failure mode seen. It is a result of excess moisture entering the lubricant, due to rain, humidity, human error, or other equipment errors.

Equipment errors include improper seals and wash down practices. Human error in this case includes improper storage methods such as lack of ventilation.

The tiniest bit of moisture in oil lubricant can reduce its lifespan by half. The less moisture in your oil lubricant, the better your equipment will perform and the less chance of failures.

Additives, which control oxidation, are also important in extending the lifespan of lubricants. These will deplete over time though, especially if other factors are increasing the moisture in the lubricant. Fix this by maintaining strong additive levels.

To keep moisture failure away, do what you can to reduce moisture levels in new lubricants, as well as eliminating moisture in stored lubricants, equipment, and wash down procedures.

Temperature

This can be caused by limited air movement, lubricant overload (main cause), incorrect cooling levels, an even using a high viscosity lubrication or the wrong viscosity.

Temperature failure happens because higher temperatures result in faster oxidation. This ultimately leads to more component wear.

Although most lubricants have a long lifespan of about 30 years, rises in temperature will majorly decrease their lifespan. Lubricants need to be kept at 70 degrees Fahrenheit. If this temperature is raised by 20 degrees, it will cut the lubricant’s lifespan in half.

Say the operating temperature for the lubricant application you have is 170 degrees, then this lubricant needs to be replaced at least once a year, twice to be on the “safe side”.

You can reduce the risk of temperature failure by using coolant, and changing it more often. Also, consider using synthetics, since they are better able to hold up to high temperatures.

Contaminants

There are several ways contaminants can enter lube. Depending on how it is stored, transported, and filtered, foreign materials are likely to get in with improper handling practices.

It is harmful to machinery if there is a large amount of foreign particles in the lube. There is only a very small amount of room for lube between a bearing or gear. If foreign particles are present, they can grid and scratch the machine’s gears.

The ISO’s (International Organization for Standardization) code for cleanliness gives us a means of knowing how many foreign particles are in the lube we purchase.

The code comes in three numbers, each determining how much contaminants of different sizes (4, 6, and 14 micron particles) are in a one millimeter sample of lube.

Depending on the level of reduction, these life extensions can get up to seven or eight times.

Working to eliminate particles from lubricants by filtering, watching for cleanliness before and during equipment use, and/or using synthetics can more than double the lifespan of a machine.

It may seem tedious or tiring to remember to take extra good care of lubrication, but it’s well worth the effort. As much as 60-80% of bearing failures (catastrophic, functional, & premature) are lubrication-related.

Smallest Ball Bearings vs Largest (Part 2)

Friday, September 4th, 2015

Last week, we focused on the world’s tiniest ball bearings, and what they are used for.

Today, we’ll shine the spotlight on the giants of the ball bearing world, and detail for you what types of applications they are used for.

In my quest for the largest ball bearing in the world, I came upon a few interesting results.

One, was the ball bearing stationed outside the SKF headquarters building in Gothenburg, Sweden. There sits an enormous, steel-looking ball, representing the company with its statuesque presence.

The second, was the Californian Benecia-Martinez Bridge, which I’ll go into more detail about now.

The Benecia-Martinez Bridge

This is actually the name for three parallel bridges spanning the Carquinez Strait from North Benecia to Suoth Martinez, in California.

It was built in 1962 to replace car ferry services across the water, and features some amazing bearing action.

Each bearing is at least 12 feet in diameter, and weighs 40,000 to 50,000 pounds. Talk about some XXXL bearings!

And, when earthquakes hit, these magnificent bearings can allow for up to six feet of horizontal movement with little to no structural displacement. That’s unparalleled.

Making the bridges durable and safe during seismic activity cost around $122 million. Now the bridges are complete with a seismic monitoring system, seismic isolation bearings, steel joints, and expansion hinges.

So, how much larger are these bearings in comparison with the miniature bearings we talked about last week?

If the bearings are 12 feet in diameter, that comes out to 8,000 times greater than miniature bearings having 1.5 mm outside diameters. Wow!

Large Bearing Manufacturing

The manufacturer I found as having the capability of producing the largest bearings, at least here in the U.S. is Messinger Bearing, out of Philadelphia, PA.

Open since 1912, Messinger Bearings specializes in designing and manufacturing bearings suited for the steel, coal pulverizing, stacker, reclaimer and tunnel boring industries. They have the capability to manufacture bearings up to 25 Feet in diameter.

According to Messinger, the largest bearing they have created so far has been 18 feet in diameter. That’s 12,000 times greater than the smallest miniature bearings with their 1.5 mm outside diameters.

Messinger transports these gigantic bearings on flatbed trucks, mounted to an A frame standing upright, and escorted by the authorities.

In case you were wondering, these mega bearings can put you back anywhere from $100-$300,000, depending on the exact needs and specifications.

Applications for these large bearings are: cranes, steel mills, draglines, tunnel boring, and more.

Now, isn’t that somethin’?

We hope you learned a thing or two about the world’s tiniest and largest bearings, what they do, and how they’re made.

Bearings continue to surprise us as innovative and useful tools in the modern age.